1. Heat energy Methods of heat transfer-how heat is moved through the atmosphere

2. Radiation Transfer of heat energy by electromagnetic waves
Transferred from sun to earth’s surface
Travels through empty space (no medium)
Examples: heat from the sun, warming hands by fireplace or hot chocolate

3. ? RADIATION How does heat energy get from the Sun to the Earth?
There are no particles between the Sun and the Earth so it CANNOT travel by conduction or by convection.
RADIATION ?

4. Convection
Transfer of heat in liquids and gases as groups of molecules move in currents
Hot rises and cold sinks
Ex: Magma inside the earth, atmosphere (weather)

5. The particles spread out and become less dense.
Convection
What happens to the particles in a liquid or a gas when you heat them?
The particles spread out and become less dense.
This effects fluid movement.
What is a fluid?
A liquid or gas.

6. Fluid movement
Cooler, more d____, fluids sink through w_____, less dense fluids.
ense
armer
In effect, warmer liquids and gases r___ up.
ise
Cooler liquids and gases s___.
ink

7. Water movement Cools at the surface Convection current Hot water rises
Cooler water sinks

8. Why is it windy at the seaside?

9. Where is the freezer compartment put in a fridge?
Cold air sinks
Where is the freezer compartment put in a fridge?
Freezer compartment
It is warmer at the bottom, so this warmer air rises and a convection current is set up.
It is put at the top, because cool air sinks, so it cools the food on the way down.

10. Conduction
Transfer of heat energy from one substance to another by direct contact
Occurs when atoms or molecules bump into each other
Has to involve touching (ex: metal touching heat source, pot handle)
Heat transfer always goes from hotter substance to cooler substance

11. Conduction
When you heat a metal strip at one end, the heat travels to the other end.
As you heat the metal, the particles vibrate, these vibrations make the adjacent particles vibrate, and so on and so on, the vibrations are passed along the metal and so is the heat. We call this?
Conduction

12. Metals are different
The outer e______ of metal atoms drift, and are free to move.
lectrons
When the metal is heated, this ‘sea of electrons’ gain k_____ energy and transfer it throughout the metal.
inetic
Insulators, such as w___ and p____, do not have this ‘sea of electrons’ which is why they do not conduct heat as well as metals.
ood
lastic

13. Why does metal feel colder than wood, if they are both at the same temperature?
Metal is a conductor, wood is an insulator. Metal conducts the heat away from your hands. Wood does not conduct the heat away from your hands as well as the metal, so the wood feels warmer than the metal.

14. List the type of heat energy for each image